Clutch and brake for direct drive spindle lathes



L. A. LEIFER CLUTCH AND BRAKE FOR DIRECT DRIVE spmoua LATHES Filed Aug. 27. 1948 3 Sheets-Sheat 2 r m e mi m WA Mn Q Q? m m A ll 6 m W MQQ .w... W N In. \Q St N\ f Hm W n u W ml & W n N l Q flflfiW/ 3 a l Q h Q. v A a Q NF.

3 P n m ,3 V 7 4., //A/ ///4 m u m m mu 3Q M N m M N mu E D L. A. LEIFER CLUTCH AND BRAKE FOR DIRECT DRIVE SPINDLE LATHES Filed Aug. 27. 1948 3 Sheets-Sheet 3 a N NA T I,Z Z T n A n 0 .L

Patented Aug. 24, 1954 CLUTCH AND BRAKE FOR DIRECT DRIVE SPINDLE LATHES Lorenz Albert Leifer, Madison,

Gisholt Machine Company,

Wis., assignor to Madison, Wis., a

corporation of Wisconsin Application August 27, 1948, Serial No. 46,385

. 2 Claims.

This invention relates to a direct drive spindle lathe wherein the spindle carries a sheave which is driven by a multiple V-belt or the like from an electric motor.

I-Ieretofore, direct spindle drives have had the sheave secured to the shaft and have necessitated the starting and stopping of the drive motor for each cycle of operation of the lathe.

Attempts to employ a mechanical clutch, such as a multiple disc clutch between the sheave and spindle have resulted in problems of actuation and of time loss that prove insurmountable. Such clutches do not produce a uniform acceleration rate and consequently are not desirable for starting heavy masses in rotation.

One of the principal objects of the present invention is to provide a direct spindle drive wherein the motor runs constantly and a clutch and brake are employed which havethe desired uniform acceleration and deceleration characteristics.

Another object of the invention is to provide a more simple direct spindle drive having a clutch and brake incorporated therein.

Another object is to provide an improved spindle control for a direct spindle drive lathe.

Another object is to reduce the time cycle of operation of a direct spindle'drive lathe.

Another object is to simplify the construction of a clutch and brake unit and its application to a direct spindle drive lathe.

Another object is to provide a clutch and brake mechanism which is self-adjusting within a large range of wear so that maintenance cost is kept at a minimum.

Another object is to provide a clutch and brake unit for controlling a direct drive spindle and in which the acceleration and deceleration curves may be kept uniform or they may be adjusted and varied at will.

The accompanying drawings illustrate a direct drive spindle lathe embodying the invention.

In the drawings:

Figure 1 is a top plan view of the headstock of the lathe;

Fig. 2 is a vertical section through the headstock taken axially of the spindle;

Fig. 3 is a transverse vertical section taken on line 3-3 of Fig. 2 centrally of the clutch and brake unit with parts broken away; and

I Fig. 4 is a wiring diagram showing the control for the clutch and brake.

2 The lathe has a headstock I in which a spindle 2 is mounted for rotation.

The front end of the spindle 2 carries a chuck 3 for securing a workpiece, and the spindle is mounted in large anti-friction bearings 4 to adapt the same to handling heavy work.

The rear end of the spindle 2 extends through the rear Wall 5 of the headstock in an antifriction bearing 6 and carries a drive sheave 1 mounted for free rotation thereon by means of ball bearings 8.

The drive sheave 7 comprises a cylindrical member having a circumferentially grooved outer surface for receiving a multiple V-belt 9 adapted to be operated by a power motor it carried adjacent the spindle by the headstock.

The bearings B are disposed in the radial space between the sheave and a sleeve ll keyed to spindle 2.

The clutch-brake unit is disposed in a longitudinal space between sheave l and the rear wall 5 of headstock l and comprises a magnetic clutch element 12 secured to the inner end of sheave l and a similarly constructed magnetic brake element I3 secured to the outer side of wall 5 of the headstock.

The clutch element [2, and likewise the brake element l3, comprises a direct current coil l4 embedded in suitable insulation [5 and. enclosed in an annular channel section metal shell 16 which is secured to the specified supporting member for the element.

A molded wear-resistant plate I! is inset in the open side of each channel it and provides a wear plate for the face of the clutch element [2 and a similar wear plate for the face of the brake element 13.

The wear plates I! face each other and are spaced apart to receive a pair of movable armature plates [8 and 19 disposed back to back therebetween.

Armature plate l8 faces the wear plate I! for clutch element I2 and is adapted to move axially toward and away from the same for clutch action. Armature plate l9 facesthe wear plate I! for brake element l3 and is adapted to move axially toward and away from the same for brake action.

Armature plates l 8 and I9 are constructed alike and each comprises a sheet metal pan facing the corresponding wear plate H and secured to rotate with spindle 2 by means of a series of pins 20 extending *therethrough longitudinally of the spindle and spaced circumferentially around the spindle. Pins 26 are secured to the spindle 2 by means of a pair of spaced flanges 2| on sleeve 5 I and a separate sleeve extension.

Each pan-like plate, I8 and I9, has a series of separate magnetic metal wear elements 22 embedded in a molded composition filling the pan.

The elements 22 extend for the full width of the corresponding channel [6 and engage the opposite edges of the channel sides to provide a closed magnetic circuit surrounding the respective coil Hi and which effects a pull upon the elements 22 by the corresponding clutch or brake element when the magnetic circuit is energized by the now of current through the coil.

When elements 22 and the corresponding plate 18 or it are pulled toward the respective corresponding element E2 or E3, the fiat faces of elements 22 engage the corresponding wear plate ii and thereby close the clutch or brake, as the case may be.

Current is supplied to clutch element l2 to en-- ergize the coils thereof by means of a pair of collector rings 23 secured upon an insulating sleeve 25% on a rotary member 25 fastened to the outer end of sheave l. Lead wires 26 pass from the corresponding coll ctor rings 23 through a hole in sheave l to the terminals 27 of the coil l4 of clutch element :22.

Current is supplied directly by suitable leads 28 to the terminals 29 of the stationary coil M of brake element i3.

Referring to the wiring diagram of Fig. 4, the motor it is supplied with current from the three phase power lines it, and a circuit breaker 3| is employed to cut the motor in and out from the lines.

A transformer 32 is connected across the lines 5% to supply current to a rectifier 33 for operating the coils H: of clutch element 12 and brake element is.

A main start and stop switch 34 is connected in the circuit of the transformer secondary to close and open the same. A relay switch 35 is connected across the secondary of the transformer 32 for operating the motor starter 36 for motor iii.

Leads El and 3B connect with the opposite output terminals of the rectifier 33 and supply current to the magnet coils I l through a two-way switch 39 which alternately and selectively energizes the respective clutch and brake coils.

The clutch is constructed with a flux curve which produces a substantially uniform acceleration for the spindle. Likewise, the brake is constructed with a flux curve which produces a substantially uniform deceleration for the spindle. An adjustable or variable resistance 48 may be connected in the return lead 38 of the circuit of the coils ill for elements [2 and I3 to provide any desired control of the acceleration and deceleration for the spindle.

The clutch plates ll and I8 and brake plates El and i9 should be free from oil at all times, and oil is prevented from reaching the plates from sheave bearing 8 by packing ring M disposed at the inner end of the bearing between an inner flange 52 on the sheave and spindle sleeve H. ihe bearing 3 is oiled by means of oil passage E3 in rotary member 25 and which is normally closed by the removable plug 44.

The passage 53 extends to the bearing chamber 65 and is preferably horizontal to indicate the level of oil in the chamber when filling. If the bearing chamber 45 is always filled when the sheave I is rotated to a position where passage 43 is at the bottom, the oil level in the chamber Will never reach the surface of sleeve El under either static or rotary conditions and there will therefore be no tendency for oil to leak past ring 4 l.

Bearing 8, as shown, preferably comprises two longitudinally spaced sets of ball races with a spacer ring between the two outer races so that the outer wall of chamber 45 is in effect provided at the radial level of the outer ball surfaces. This fact results in the spreading of the oil in chamber 55 under centrifugal action produced by rotation of the outer chamber wall with sheave i into a thin film through which the bearing balls 46 run, thereby effecting an adequate oiling of the bearing without permitting the oil to reach the spindle sleeve I l and to leak through packing washer M.

A housing ill is secured to the headstock and surrounds the clutch and brake mechanism to additionally protect the frictional plate surfaces of the clutch and brake.

The invention provides a spindle control which is greatly improved over prior direct drive spindies. The electrically operated clutch and brake mechanism provides a very rapid and effective control means having the most efrlcient acceleration and deceleration characteristics. tioning and arrangement of the magnetic clutch and brake between the sheave and headstock serves to protect the clutch and brake against injury and provide a compact and simple assembly construction which utilizes the energy of the rotating sheave, belt and motor to assist in providing the necessary acceleration torque. The provision for limiting the oil in the bearings assures the maintaining of the frictional surfaces of the clutch and brake plates and collector rings free from oil.

The invention is hereby claimed as follows:

1. In a power drive including a base, a horizontal rotary member supported by said base, a drive member rotating continuously in one direction, and brake and clutch means selectively connecting said members to rotate the rotary driven member connecting the member and base to stop the rotation of said member, said brake and clutch means respectively including electro-magnetic elements and friction means to engage the corresponding elements upon energization of the elements, said brake and clutch means requiring the dry operation of elements and friction means thereof maximum torque capacity; means said brake element to said base with the end of the rotary member extending therethrough, said drive member having bearings supporting the same for rotation on said end of the rotary member and carrying said clutch element in axiall spaced and opposite relation to said brake element, means carried by said rotary member and supporting said friction means between said brake and clutch el ments, said brake element remaining stationary and said clutch element being adapted for continuous rotation with said drive member, said drive member forming a housing and with said rotary member defining annular sealed chamber enclosing said bearings and including an outer and end walls formed by and rotating with the drive mermber, housing being adapted to be filled with a liquid for lubricating said bearings, said liquid being maintained entirely within the housing of said drive member to preclude leakage to said elements and friction means by the continuous The posirotation thereof and otherwise being of limited References Cited in the file of this patent supply and wholly within the capacity of the UNITED STATES PATENTS lower part of sand chamber beneath said driven member Number Name Date 2. The invention as defined in claim 1 wherein 5 112971 Sheldon Man 211 1871 the clutch element is provided with electrical cur- 914375 A513 1- 9, 1909 rent supply means including collector rings car- 1,130,341 Smfield 2, 1915 ried by the drive member for continuous rotation 14551124 Berger Sept 1915 therewith and the rotation of the housing formed 1593307 LODFS July 1926 by said drive member further precludes the leak- 10 2467390 wmtehead et 1939 age of the lubricating liquid to said rings during 23721757 Teher 10) 1940 t Operation of t drive 0 Bi k l June 1 1 1 

